H04M 3 - Automatic or semi-automatic exchanges

Patents for H04M 3 - Automatic or semi-automatic exchanges (99,881)
12/1980
12/02/1980	CA1090927A1 Analog signal summing conference circuit
12/02/1980	CA1090909A1 Communication system using intelligent network processor
12/02/1980	CA1090908A1 Communication system call coverage arrangements
11/1980
11/27/1980	WO1980002628A1 Device control system
11/27/1980	WO1980002627A1 Voice controlled switching system
11/26/1980	EP0019245A1 Device control system
11/25/1980	CA1090497A1 Line current detection
11/25/1980	CA1090496A1 Telephone control console
11/18/1980	US4234763 Feeding bridge with d.c.-compensation for both directions of the feed current
11/12/1980	EP0018859A1 Ringing control device
11/12/1980	EP0018844A1 Telephone systems
11/12/1980	EP0018834A1 Improvements in or relating to telephone exchanges
11/11/1980	US4233471 Automatic telecommunication exchange system
11/04/1980	US4232199 Special services add-on for dial pulse activated telephone switching office
11/04/1980	US4232198 Device for establishing conference calls via at least one telephone exchange switching system
11/04/1980	CA1089130A2 Telephone apparatus
11/04/1980	CA1089019A1 Digital binary group call circuitry arrangement
10/1980
10/29/1980	EP0017898A1 Radio installation
10/29/1980	EP0017835A1 Circuitry for controlling the transmission of digital signals, especially PCM signals, between connection points of a time division multiplexing telecommunication network, especially a PCM network
10/29/1980	EP0017764A1 Subscriber line circuit with ground key activation indication, high ohmic commutable feeding and apparatus for ringing-signal generation
10/29/1980	EP0017763A1 Subscriber line circuit with ground key activation indication and insulation fault indication
10/28/1980	US4230908 Telephone summing circuit
10/28/1980	CA1088684A1 Loop current detector
10/28/1980	CA1088683A1 Calling circuit
10/21/1980	US4229814 Multiplex conference bridge
10/21/1980	US4229691 Electrical testing of cords terminated with modular plugs
10/21/1980	US4229624 Switching network control arrangement
10/21/1980	CA1088234A1 Test circuit for a protective coupler
10/14/1980	US4228328 Signal distributor test arrangement
10/14/1980	CA1087702A1 Traffic usage data gathering apparatus
10/02/1980	WO1980002095A1 Telephone-conferencing apparatus and method
10/02/1980	WO1980002094A1 Communication system tracking arrangement
10/01/1980	EP0016672A1 Call device for an automatic subscriber telephone installation with extensions
09/1980
09/30/1980	US4225956 Multiplex conference bridge
09/30/1980	CA1086880A1 Operator supervisory circuit for a key telephone system
09/23/1980	US4224688 Digital conference circuit
09/23/1980	US4224479 Method of controlling call traffic in a communication switching system
09/09/1980	US4221936 Loop to ground start circuit
09/09/1980	US4221933 Data storage and retrieval structure for a message storage system
09/02/1980	US4220826 Ringing generator
09/02/1980	US4220825 Telephone status monitor circit
08/1980
08/26/1980	US4219701 Tone generating hold impedance circuit for key telephone line circuits
08/19/1980	US4218592 Telephone analyzer for detection of clandestine devices
08/12/1980	CA1083734A1 Key telephone line circuit tone-on-hold arrangement
08/06/1980	EP0014044A1 Method and system for reducing conference bridge oscillations
08/05/1980	US4216355 Telephone line monitoring apparatus
07/1980
07/29/1980	US4215251 Switching apparatus selectively utilizing a regenerative repeater
07/29/1980	US4215247 Digital conferencing apparatus
07/22/1980	CA1082380A1 Telephone system for automatic redialing of busy numbers
07/22/1980	CA1082379A1 Telephone isolation system
07/15/1980	US4213016 Arrangement for measuring the line condition of a subscriber's line circuit by means of a measuring resistor
07/15/1980	US4213013 Telephone network/subscriber interface device
07/15/1980	CA1081875A1 Digital measurement of the dc value in an ac signal adapted to telephone off-hook detection
07/15/1980	CA1081831A1 Conference circuit for pulse coded modulated telephony
07/08/1980	US4211896 Subscriber's circuit with a symmetrical amplifier
07/01/1980	US4210783 Digitally controlled telephone answering switching system
07/01/1980	CA1080869A1 Electronic hybrid and hybrid repeater
07/01/1980	CA1080865A2 Out-of band signaling method and apparatus to adapt payphones to telephone systems
07/01/1980	CA1080834A1 Arrangement for controlling seizure of a connector
06/1980
06/26/1980	WO1980001349A1 Data storage and retrieval structure for a message storage system
06/25/1980	EP0012642A1 Testing device for a time division switching network
06/25/1980	EP0012185A1 Test circuit for synchronously operating clock generators
06/24/1980	US4209671 Method and apparatus for testing the tip-ring polarity of telephone receptacles connected in parallel to a non-working pair
06/17/1980	US4208553 Telephone office assignment verification
06/17/1980	US4208552 Malfunction-detecting equipment for real-time supervision of central-office circuits in telecommunication system
06/17/1980	CA1079881A1 Key telephone lamp control circuit
06/17/1980	CA1079880A1 Key telephone system signal priority arrangement
06/17/1980	CA1079879A1 Line circuit for key telephone systems
06/11/1980	EP0011750A1 Circuit for detecting the busy state of a telephone line
06/11/1980	EP0011720A1 Circuitry for suppressing the influence of interfering voltages at the evaluation of the condition of a signal on transmission lines, particularly on subscriber lines in telephone installations
05/1980
05/27/1980	CA1078499A1 Telephone multiline automatic voice answer system
05/20/1980	US4204241 Low power consumption relay switching circuit for use in conjunction with a line test trunk interfacing to a test desk
05/20/1980	CA1078048A1 Method of and arrangement for switching a service information
05/15/1980	WO1980001028A1 Signal switching device through optical means and self switches comprising such device
05/14/1980	EP0010720A1 Fully electronic loop closure circuit
05/13/1980	US4203005 Digital type telephone system having a conference function
05/06/1980	US4202025 Polysiloxane-polycarbonate copolymer adhesive and polyvinylidene chloride
05/06/1980	US4201896 Telephone polling apparatus using a plurality of timers to detect the line conditions
05/06/1980	CA1077160A1 Arrangement for monitoring live call disposition signals
04/1980
04/29/1980	US4200772 Computer controlled telephone answering system
04/29/1980	US4200771 Traffic measuring device based on state transitions
04/29/1980	CA1076725A1 Attendant console control system
04/22/1980	US4199664 Telephone line circuit
04/22/1980	CA1076279A1 Key telephone adapter for electronic telephone switching system
04/17/1980	WO1980000773A1 A traffic measuring device based on state transitions
04/08/1980	US4197435 Telephone line monitoring circuit and method
04/08/1980	US4197430 Operator service position system
04/08/1980	US4197429 Gain-adjusting conference circuit
04/08/1980	CA1075384A1 Conferencing arrangement for use in a pcm system
04/08/1980	CA1075383A1 Conferencing arrangement for use in a pcm system
04/02/1980	EP0009051A1 Telephone system with a plurality of internal extensions and a plurality of outside lines
04/01/1980	CA1074935A1 Subscriber equipment for telephone exchange
04/01/1980	CA1074933A1 Apparatus for subscriber testing of a telephone line
04/01/1980	CA1074894A1 Automatic call distribution system
03/1980
03/25/1980	US4195206 Path test apparatus and method
03/25/1980	CA1074426A1 Means for identifying subscriber lines
03/25/1980	CA1074425A1 Decoupling control arrangement for auxiliary circuits coupled to telephone lines
03/19/1980	EP0008695A1 Circuit arrangement for telephonic switching systems, particularly private branch exchanges, with auxiliary data traffic, e.g. with teleprinters
03/18/1980	US4194098 Lineman's hand test set
03/18/1980	CA1073994A1 Conference circuit for pulse coded modulated telephony

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